The invention relates to a sanitary line attachment which is of sleeve-shape design in at least one front end region and, in the sleeve interior of said sleeve-shaped front end region, bears an internal thread for attachment to an adjacent line portion, wherein a sealing ring is provided which is produced from a dimensionally stable and/or inelastic material and is provided for sealing clamping between the line attachment and the adjacent line portion, the ring outer circumference of which sealing ring has at least one protruding holding projection, which holding projection engages in the internal thread in the sleeve interior of the sleeve-shaped front end region, wherein the sealing ring has at least one indentation.
U.S. Pat. No. 4,088,327 A discloses a sanitary line attachment of the type mentioned at the beginning which has a sleeve-shaped attachment piece, in the sleeve interior of which an internal thread is provided. The attachment piece provided for attachment to an adjacent line portion is assigned a sealing ring for sealing clamping between the line attachment and the adjacent line portion. The ring outer circumference of said sealing ring has holding projections which are spaced apart from one another, engage in the internal thread in the sleeve interior of the sleeve-shaped attachment piece and secure the sealing ring there against falling out. The sealing ring used in the previously known line attachment has an indentation which is designed as an aperture in the ring circumference of the sealing ring and permits expansion and constriction of the sealing ring in its sealing ring circumference and therefore adaptation of the sealing ring to the various clear diameters of differently dimensioned attachment pieces.
U.S. Pat. Nos. 1,157,574 A and 1,917,553 A already disclose sanitary line connections which likewise serve for the connection of adjacent line portions. While a sleeve-shaped coupling piece with an internal thread is provided on the one line portion, the adjacent other line portion has a coupling counterpart, which coupling counterpart can be screwed with an external thread into the internal thread of the line portion first mentioned. Provided between the opposite front ends of the interconnectable line portions is a sealing ring which is made from an elastic material and the ring outer circumference of which has a plurality of holding projections which are spaced apart from one another in the circumferential direction and engage in the internal thread in the sleeve interior of the sleeve-shaped first line portion.
EP 1 770 225 B1 already discloses a sanitary line attachment which is of sleeve-shaped design in at least one front end region, wherein an internal thread is provided in the sleeve interior of said sleeve-shaped front end region, said internal thread serving for attachment to an inflow- or outflow-side line portion. A sealing ring is clamped in a sealing manner in the front end region between the previously known line attachment and the adjacent line portion, on the outer circumference of which sealing ring a plurality of holding projections protrude, said holding projections being spaced apart at uniform distances from one another and engaging in the internal thread in the sleeve interior of the sleeve-shaped front end region. Said holding projections protrude on the outer circumference of the sealing ring in such a manner that the holding projections can engage in the internal thread and can be fixedly clamped there. In this manner, the sealing ring and, with the latter, the components additionally provided in the sleeve interior of the previously known line attachment are secured in such a manner that said components cannot be unintentionally released, for example due to transport-induced vibrations, but nevertheless can be easily separated from one another when required.
However, sealing rings made from elastic material are less readily suitable in various application sectors. Some of such application sectors require the use of fiber seals. Comparably configured fiber seals cannot, for example, be pressed into a sleeve-shaped union nut because of the little elasticity and the high dimensional stability of the material which is used since the holding projections on the ring outer circumference of such a sealing ring would break off in the process. Such fiber seals therefore have had to be added separately up to now or connected to an attachment tube during the storage and the transport of the latter. However, there is the risk here of said ring seals being overlooked by the user or being fitted incorrectly or even not at all.